Every Mac since 1993 has awaked with a signature startup chime. Its presence signals a succesful passage of the initial hardware and firmware checks. Its absence, however, could aid introubleshooting a failed boot attempt. The tone became so associated with Apple that they trademarked the F-sharp major chord. This traditional sound (along with the glowing Apple logo) will end with the release of the Late-2016 Macbook Pro.
There was always a way to silence the chime with a few command lines in Terminal. Thankfully, lovers of the chime can reactivate it with a single line of code. Just open Spotlight and search for Terminal. Once it has opened a command line simply type sudo nvram BootAudio=%01 and the chime will return on your next reboot.
There was always something comforting about hearing that chord and then seeing your desktop spring to life. Personally, I’m looking forward to hearing it again.